What is the best example of self confidence in an interview?

Self-confidence is portrayed in many ways, not just one…Being prepared for the interview, a professional appearance, good eye contact, clear concise responses to questions, ability to not melt under pressure. As well as a great attitude that shows hire me or not hire me, I will be great either way! Confidence vs. arrogance. Mirroring your interviewer has been proven to be very effective in showing likability as well.

Hope this helps!